[dojox.layout] ExpandoPane doesn't handle being hidden initially

Description

The _titleHeight is calculated in startup, but should probably be extracted into a secondary function only fired once immediately before an initial resize() call, to ensure the pane is visible (like being in a selected tab) before doing the calculations and animation creation.

(In [16553]) fixes #8531 - defer resize until after initial visibility setup. also lots of css fixes. attemps to fix but does not #8569, though the tabs have the right height, their controller is too small.
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